Since an obstacle slows the wind for a distance of ____ times its height, vegetation some distance from the roadside may require control to prevent snowdrifts.

Since an obstacle slows the wind for a distance of ____ times its height, vegetation some distance from the roadside may require control to prevent snowdrifts.

• A. 5-10
• B. 10-15
• C. 15-20
• D. 20-25

Answer: (C)

Wind slows down on the downwind side of an obstacle, creating a wind shadow that can cause snow to settle out of the air and form drifts. A good rule of thumb is that this wind-slowing effect extends about 15 to 20 times the obstacle’s height. So vegetation located at that distance or within it can influence where snow drifts form and may need management to prevent snow buildup near the road. For example, a shrub 6 feet tall can affect wind up to roughly 90 to 120 feet downwind, increasing the potential for drift near the roadside if not controlled.

Wind slows down on the downwind side of an obstacle, creating a wind shadow that can cause snow to settle out of the air and form drifts. A good rule of thumb is that this wind-slowing effect extends about 15 to 20 times the obstacle’s height. So vegetation located at that distance or within it can influence where snow drifts form and may need management to prevent snow buildup near the road. For example, a shrub 6 feet tall can affect wind up to roughly 90 to 120 feet downwind, increasing the potential for drift near the roadside if not controlled.